1. Field of the Invention
The present invention relates to a control device for a vertical shaft type engine.
2. Description of the Prior Art
In a typical lawn mower on which a vertical shaft type engine is mounted, control of the engine is effected by means of single manipulation lever or acceleration control. Thus, it is necessary to provide an engine control device capable of achieving all the functions of stoppage, rotational speed regulation and choking.
Such prior art control device, as shown in FIGS. 7(a) and 7(b), includes a control lever 3 rotatably mounted on a control panel 9 provided with a stop switch terminal 10, and one end of the control lever 3 can be brought into contact with a choke control plate 4.
A Bowden wire 1 has its outer cable fixedly secured to the control panel 9 by means of a wire clamp 8(A). An inner cable 2 of the Bowden wire 1 is moved in the forward and backward directions by manipulating a manipulation or acceleration control lever 21 on a working machine H, e.g. a lawn mower, as shown in FIGS. 8(a), 8(b) and 9, and one end of the inner cable 2 is connected to the control lever 3 (FIG. 7(a)). When the control lever 3 is moved to a position closest to the wire clamp 8(A), it comes into contact with the stop switch terminal 10 to stop an engine E as shown in FIG. 7(a), while when lever 3 is moved to a position farthest from the wire clamp 8(A), a rotational speed regulating screw 6 provided on the control lever 3 comes into contact with the choke control plate 4 and rotates the choke control plate 4, and the construction is such that a choke valve in a carburetor, not shown, is closed by a choke rod 5 connected to the choke control plate 4.
The rotational speed of the engine E is controlled by expanding and contracting a governor spring 7 engaged with the control lever 3 in accordance with rotation of the control lever 3, thus moving a governor lever (not shown) engaged with the other end of the governor spring 7 and regulating an opening angle of a carburetor throttle valve (not shown) connected to the governor lever. When the control lever 3 is close to the stop switch terminal 10 of the engine E, the engine E rotates at a low speed, but just before the control lever 3 comes into contact with the choke control lever 4, the engine rotates at a high speed.
The lever 21 on the working machine H for controlling the engine E may be of the type such that engine E is accelerated to a high speed when the inner cable 2 of the Bowden wire 1 is moved in a projecting direction as shown in FIG. 9. Alternatively, lever 21 may be of the type such that the engine E is accelerated to a high speed when the inner cable 2 of the Bowden wire 1 is moved in a retracting direction. Consequently, in the case of a control device having such structure that when lever 21 on a working machine H is manipulated in the direction of projecting inner cable 2 of Bowden wire 1, the engine E is accelerated to a high speed as shown in FIG. 9, a wire clamp position with respect to the control panel 9 is selected to be 8(A) in FIG. 7(a), while in the case of a control device having such structure that when lever 21 on the working machine H is manipulated in the direction of retracting the inner cable 2 of the Bowden wire 1, the engine E is accelerated to a high speed, the wire clamp position with respect to the control panel 9 is selected to be 8(B) in FIG. 7(a).
In FIGS. 8(a) and 8(b) are shown two examples of mounting orientation or attitude of an engine according to the prior art, in the case where the engine E is choked when lever 21 of the working machine H is manipulated in the direction of projecting the inner cable 2 of the Bowden wire 1. Since the stop switch terminal 10 is located in the direction of mounting of an ignition plug 22 on the engine E, in order to minimize the length of the inner cable 2 of the Bowden wire 1 on the working machine H, the only possible attitudes of mounting of an engine are the two varieties shown in FIGS. 8(a) and 8(b).
In the engine control device in the prior art in which an engine is manipulated from "stoppage" to "choking" by means of a single Bowden wire, there is a disadvantage that in order to simplify routing of the Bowden wire 1 the mounting attitude of the engine is restricted, depending upon the direction of manipulation of lever 21 on a working machine H, that is, depending upon whether the engine is accelerated to a high speed when the inner cable 2 of the Bowden wire 1 is projected or retracted, as described above.
In the case where the working machine H has such structure that it is accelerated to a high speed when the inner cable 2 is projected, only the mounting positions of the engine as shown in FIGS. 8(a) and 8(b) are practical, and it is difficult to select a position where the ignition plug 22 is directed in the travelling direction of the working machine for the purpose of facilitating maintenance operations.